Automatic circuit breaker



Aug. 6, 1940. J. sAcHs 2.219263 AUTOMATIC CIICUIT BREAKER Filed web. 27,1959 (l KOR,

Patented Aug. 6, 1940 AUTOMATIC CIRCUIT BREAKER.

Joseph Sachs, West Hartford, Conn., assignor to Colts Patent Fire ArmsManufacturing Company, Hartford, Conn., a corporationof ConnecticutApplication February 27, 1939, Serial No. 258,704

-4 Claims. (Cl. 200-113) In accordance with the present invention Iprovide a circuit breaker incorporating, in modied and simple form,certain of the features set forth in my Reissue 4Patent No. 20,018, inmy Patents 1,812,846 and 2,131,640, all entitled Automatic circuitbreaker, and also certain of the features set forth in the copendingapplication of Sachs and Christensen Serial No. 202,295 entitledAutomatic circuit breaker. I provide a bodily movablethermally-responsive bi-metallic element which serves as a resilientconnection between a toggle and the movable switch member. Normally theresilient element holds the toggle in overset position and thusvholdsthe switch member in closed-circuit position, but upon the attainment ofan excess current condition the bi metallic element is heated and isdeected in the direction to reduce the Apressure on the toggle, thuspermitting the toggle to move so as to release' the switch -member forcircuit-opening movement.

In the accompanying drawing I have shown the embodiment of the inventionwhich I now deem preferable, but it will be understood that the drawingis intended for illustrative purposes only and is not to be construed asdening or limit ing the scope of the invention, the claims forming apart of this specification being relied upon for that purpose.

Of the drawing:

Fig.1 is a front view of a circuit breaker embodying the invention.

Fig. 2 is a vertical sectional view taken along the line 2 2 of Fig. 1and showing the movable parts in closed-circuit positions.

Fig. 3 is a fragmentary sectional view taken along the line 3-3 of Fig.2.

' Fig. 4 is a view similar to Fig. 2 but showing the movable parts inopen-circuit positions..

Referring to the drawing, I represents as an entirety a casing'orhousing which is shown as molded from a suitable insulating material.This iousi'ng is closed at the sidesand is substantially :lo'sed at theends and at the rear, but it is open at the front where there isprovided a removable insulating cover 2 normally held in place by ;crews3, 3.

A stationary contact 4 is mounted within the iousing l near the rearthereof, this contact beng carriedby a conductor held in place by alcrew 6. A nut 'I on the'screw 6 cooperates with he conductor 5 toconstitute a wire terminal.

ilsc mounted on the housing is a stationary lonductor 8 held in place bya screw 9. Connected with the conductor 8 is a suitable wire connectingterminal such as a nut I 0.

Mlovably Imounted within the housing I is a contact carrying member I Iwhich is shown-as being pivotally movable, being mounted upon 'a 5transverse pivot pin I2 which extends transversely between the sidewalls of the housing I. The contact member II carries a movable contactI3 adapted to engage the stationary contact 4 as shown in Fig. 1. Thecontact member II is biasedior movement in the circuit-opening orcontact disengaging direction by means of a spring I4. As shown thecontact member II extends ,through a hole in a movable insulating baffleplate I5 guided in grooves in the sidewalls 15 of the housing. Thisbaille plate `serves to `separate the arcing zone at the contacts fromthe mechanism of the circuit breaker.

A pivotally movable operating member I6 is provided, this being mountedon a pivot pin I1 20 which extends transversely between the side wallsof the housing I. This operating member extends s through a suitableopening in the front cover 2 of the housing, and it is Ybiased formovement in the clockwise 'or circuit-opening direction by 25 means of aspring I8. A transverse stop pin I9 limits the movement of the operatingmember in the counterclockwise direction.

Pivotally connected with the operating member at is a -link 2|, thispreferably comprising two 30 similar parts positioned at opposite sidesof the, operating member. yThe link 2I and the operating member I6 areadapted to cooperate with each other and form a toggle which operates inthe manner to be described.

A resilient mechanical connection is provided between the link 2l andthe contact member Il, and in accordance with the present invention thisresilient connection is provided by means of a thermally-responsivebi-metallic element or strip 22. This bi-inetallic element is rigidlyconnected at its lower end with the contact member II, the said memberhaving an integral forward extension -I Ia which projects through a holein the strip. ,Metallic washers 23 and 24 are pro- 45 vided at bothsides of the element 22 and all of these parts are held in fixedrelationship by riveting over the forward end of the extension IIa asclearly shown in Fig. 2. At or nearits upper end, the bi-metallicelement- 22 carries a yoke 50 25 which is pivotally connected at 26 withthe link 2|. A means is provided for causing the bi-metallic element tobe heated and deilectecl upon the attainment of excess currentconditions in the circuit. .As shown the bi-metallic element is directlyconnected in the circuit so as to carry current, and for this purposethere is provided a emble electrical conductor 21 which is electricallyconnected at one end with the upper end of the bi-metallic element. sshown, this conshown in Fig. 2, the circuit extends from the con-y tacts4 and I3 through the contact member Il to the bi-metallic element 22,and from the bimetallic element 22 the circuit extends through theexible conductor 2l to the stationary con-,-

ductor 8.

The bi-metallic element 22 is resilient and Fig. z shows this as`slightly exed, this element applying pressure in the forward directionto the toggle which consists of the link 2l and the operating member I6.This pressure serves to hold the toggle in its overset position asshown, and thus the said strip in connection lwith the toggle serves tohold the contact member in the closed-circuit position and'to apply thenecessary pressure at the contacts I3 and II. It will be obvious that bymoving the operating member in' the clockwise diretcion the toggle canbe broken or released so as to permit the movable parts to move to theiropen-circuit positions as shown in Fig. 4. It will be observed that thetoggle serves directly to hold the movable contact in engagement withthe stationary contact, the actual contact pressure being transmitteddirectly through the toggle. The bif-metallic element 22, when heated,tends to deflect in the rearward direction, but it is s'o proportionedanddesigned that under normal current itdoes not deect to such an extentas to reduce the toggle pressure sufliciently to permit the toggle toopen. However, when.- excess current conditions are attained in thecircuit the bi-metallic element 22 deilects rearward to an extentgreater than normal, thus reducing the Apressure on the toggle to suchan extent that the toggle is broken by means of the spring I8. The

parts then move automatically to their opencircuit positions shown inFig." 4, such movement taking place under the combined'iniluence of thesprings I8 and I4. After the parts havel thus moved to the positionsshown in Fig. 14 they can be restored manually to their normalclosedcircuit positions as soon as the bi-metallic element 22 has cooledso as to return to its unexed condition.

It will be observed that I have provided a resilient connection betweenthe operating member and the contact member, this being in accordancewith-the invention set forth and claimed in the before-mentioned Sachs`and Christensen application Serial No. 202,295. It is thereforepreferamants pressure but which-upon 'reduction ofthe contact pressurebelow a predetermined permits the circuit breaker'to operateautomatically L to open the circuit.

What I claim is: 1. An automatic circuit breaker comprising incombination, a stationary contact, a movable con- 'tact member having amovable contact adapted to engage and disengage the stationary contactwhich member is biased toward its open-circuit position, a resilientbi-metallic element rigidly connected at one end with the contactmember, a

toggle having one link connected with the remain,

ing end of the bi-metallic element. and thereby directly vserving whenin overset position to hold the movable contact member in closed-circuitposition, the said toggle being held in its overset position by pressureexerted thereon by the said resilient element, meansfor biasing thetoggle for movement out of the overset position, and means serving uponthe attainment of fan excess current condition in the circuit to` causethe bi-metallic element to be heated and to be deflected in thedirection to reduce -the pressure on the toggle thereby permitting thetoggle to move so as to release the contact member for automaticcircuitopening movement. v r f l 2. An automatic circuit breakercomprising in combination, a rigidly supported stationary contact, acontact member guided for movement in a fixed path and. including amovable contact rigidly carried thereby and adapted to engage anddisengage the stationary contact which member is biased toward itsopen-circuit position, a resilient bi-metallic element rigidly connectedat one end with the contact member, a toggle having one link connectedwith the remaining end of the bi-metallic element and thereby directly.serving when in overset position to hold the movable contact mem- .berin closed-circuit position, the said toggle :being heldin its oversetposition` by pressure attainment of an excess current condition in thecircuit to cause the bimetallic element to` be heated and to bedeiiected in the directionv to reduce the pressure on the toggle therebypermitting the toggle to move so as to vrelease the contact member forautomatic circuit-opening movement.

, 3. An automatic circuit breaker comprising in combination, astationary contact, a movable contact member having a movable contactadapted to' engage and disengage the stationary contact which member is.biased toward its opencircuit position, a resilient bi-rnetallicelement rigidly connected at one end with the contact member, a

toggle. having one link connected with the remainingl end of theVbi-metallic` element and thereby directly serving whenv inoversetposition to hold the 'movable contact member in closedcircuitposition, the said toggle being held in its overset position by pressureexerted thereon by. the said resilient element, means for'biasing thetoggle for movementout of the overset position, and means for connectingthe bi-metallic element in the circuit in xseries with the contacts sothat upon the attainment of an excess current condition in the circuitit is heated and is deilected in the direction to reduce the pressure onthe toggle thereby permitting the toggle to move so as to release thecontact memberforautomatic circuitopening movement.`

4. An automatic circuit breaker comprising in combination, a rigidlysupported stationary conbiased toward. its open-circuit position, aresilient loi-metallic element rigidly connected at one end with thecontact member, a pivotally movable operating member, a link pivotallyconnected at one end with the operating member and at the other end withthe remaining end of the loi-metallic element, the said link cooperatingwith the operating member to form a toggle which directly serves when inoverset position to hold the movable contact member in closed-circuitposition and which is normally held in its overset position by pressureexerted thereon by the said resilient element, means for biasing thetoggle for movement out of the overset position, and means forconnecting the bi-metallc element in the circuit in series with thecontacts so that upon the attainment of an excess current condition inthe circuit it is heated and is deflected in the direction to reduce thepressure on the toggle thereby permitting the toggle to move so as torelease the contact member for automatic circuit-opening movement.

JOSEPH SACHS.

